6Bottiger M.The elimination of polio in the Scandinavian countries[J].Public Health Review,1993,21:27-23.
7Foiore L,Novello F,Simeon P.Surveillance of acute flaccid paralysis in Italy:1996-1997[J].European J Epidemiol,1999,15:757-763.
8Andrus JK,Strebel PM,de Quadros CA,et al.Risk of vaccine-associated paralytic poliomyelitis in Latin America,1989-1991[J].Bull WHO,1995,73:33-40.
9Nkowane BM,Wassilak SGF,Orenstein WA,et al.Vaccine-associated paralytic poliomyelitis.United States:1973 through 1984[J].JAMA,1987,257:1335-1340.
10Strebel PM,Sutter RW,Cochi SL,et al.Epidemiology of poliomyelitis in the United States one decade after the last reported case of indigenous wild virus-associated disease[J].Clin Infect Dis,1992,14:568-579.
